DESCRIPTION: The major objective of the proposed work is to exactly replicate studies reported by Benane et al. (1996) in which Clone 9 cells, treated with concentrations of chloral hydrate which partially inhibit gap junctional intercellular communication (GJIC), are exposed to power frequency, i.e. extremely-low-frequency (ELF), electromagnetic fields (EMFs). A further reduction in GJIC produced by the ELF-EMF was reported to be consistent with the Ion Parametric Resonance (IPR) model, proposed by Blackman et al. (1993), which predicts distinct magnetic field interactions with biological systems. Equipment and an expertise in all relevant experimental techniques is already in place to perform these replication studies at Oak Ridge National Laboratory (ORNL). If the same results are observed using an identical exposure system as that used by Blackman and co-workers, then the consistency of the effect will be examined under the constraints of a different exposure system and modifications of the experimental protocol. The dedicated magnetic field exposure system at ORNL, which is one of four regional facilities in the United States, will be used to repeat, and expand the replication studies. This exposure system was designed to provide carefully controlled conditions for cell culture exposures to magnetic fields. In addition, extensive experience in the principal investigator's laboratory with GJIC studies suggests possible improvements in the experimental techniques used to measure GJIC. Modifications in scrape-loading procedures and the use of electrophysiology measurements are proposed for these subsequent studies of cell-to-cell coupling. If the main objectives, outlined above, substantiate the results reported by Blackman and co-workers then emphasis will be shifted to experiments aimed at understanding the mechanisms involved.